In the context of China's implementation of territorial spatial planning, green infrastructure (GI) in urban built-up areas and city regions forms a two-tier planning system. This results in inadequate connections and transitions between the two scales of GI. Boundary Green Infrastructure (BGI) is a type of GI situated at the boundary of urban built-up areas. It has the capacity to transform ecological functions and human activities, serving as a link between the ecological spaces of built-up areas and city regions. This paper focuses on BGI patches as the primary research subject and studies the spatial patterns of BGI patches in nine European cities: 1) Proposing the concept of ‘function transition bridge' and categorizing them into two types: Green-Bridge and Human-Bridge, which undertake the transfer of biological flows and the connection of human activities. Utilizing the pixel classification model in deep learning with ArcGIS Pro to assist in identifying spatial elements within the patches, in conjunction with remote sensing imagery and land use types in the study area to generate a spatial pattern map of BGI patches using the Landscape Pattern Language method. 3) Using the Morphological Spatial Pattern Analysis (MSPA) method and analyzing point of view (POI) data to identify the spatial characteristics of patches from both spatial and functional perspectives, including the four key area characteristics: aggregation and dispersal characteristics, transition function characteristics, and core human activity characteristics to establish the BGI patch spatial characteristic index system. This paper enriches the research results in the field of BGI, fills the research gaps at the BGI patch level, and provides references for improving the integrity of urban GI networks and NBS-based planning strategies.